Thermostat Replacement repair in Orlando, FL

Verified against official sources · Updated 2026-07-06

Thinking about a thermostat replacement repair in the Orlando area? Here's what actually matters — permit rules for Orange County and the City of Orlando, plus the mistakes and code requirements that trip up homeowners, sourced from manufacturer manuals and the Florida Building Code.

Do you need a permit?

It depends on the exact scope. Orange County and the City of Orlando require permits for more than most homeowners expect — and the rules change. Check the county's official "Do I Need a Permit?" page or call your local building department before starting work.

Key facts before you start

Kill the HVAC breaker (or air-handler switch) before touching any wire — Google's install docs require power off before connecting/disconnecting wires; a shorted wire pops the 3–5A fuse on the air-handler control board and the whole system goes dead (Nest E298/E448 'no power' codes).
Verify 24V low-voltage first: line-voltage baseboard heat (110–240 VAC, thick wires), millivolt wall heaters, and proprietary/communicating systems (wires labeled 1/2/3 or A/B/C) are NOT compatible with Nest/ecobee/Honeywell smart stats — run Google's online Compatibility Checker before buying.
Photograph the old wiring with terminal letters legible before pulling any wire — there is NO standard thermostat wire color code (Honeywell official guidance); label wires and tape them so they don't fall into the wall.
C-wire: heat pump and zoned systems require a C wire or power accessory on Nest (power-sharing alone causes battery drain/Wi-Fi drops — fix with Nest Power Connector); ecobee ships a Power Extender Kit that installs at the air-handler board using the existing R/G/Y/W (needs 4+ wires, 24VAC single-transformer only).
Central FL homes are mostly heat pumps: the orange wire lands on O/B and the reversing-valve orientation must be set to O (energize-in-cool, the Nest default and standard for FL brands like Trane/Carrier/Rheem). If the system blows cold on heat or warm on cool, flip the O/B setting — don't rewire.
R/Rc jumper: one R wire = leave the factory R–Rc jumper/slider in place (1-wire position); separate Rh + Rc wires (two transformers) = remove the jumper or the transformers cross-connect. Note ecobee's PEK is incompatible with dual-transformer systems.

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Sources

https://support.google.com/googlenest/answer/9244071?hl=en
https://support.google.com/googlehome/answer/10191637?hl=en
https://support.google.com/googlehome/answer/9246656?hl=en
https://support.google.com/googlehome/answer/9251212?hl=en
https://support.google.com/googlenest/answer/10523126?hl=en
https://support.ecobee.com/s/articles/Installing-your-ecobee-thermostat-with-the-Power-Extender-Kit-no-C-wire
https://www.honeywellhome.com/blogs/support/how-do-i-wire-my-thermostat
https://www.honeywellhome.com/blogs/support/what-is-the-r-slider-tab
https://support.google.com/googlenest/answer/15826506?hl=en
https://support.google.com/googlehome/answer/9452748?hl=en

This guide is general informational content, not professional or legal advice. Codes and county rules change — confirm permit requirements with your local building department, and use a licensed professional for electrical, gas, structural, or main-line plumbing work.